Accelerated ripening of cheese to improve cost efficiency through reduction of storage time is important to the cheese industry. Techniques which are currently being evaluated include elevation of storage temperature, culture modifications, addition of enzymes such as proteases and lipases and combinations thereof. Accelerated ripening has limited commercial value due to inherent problems in controlling available techniques. For example, the use of elevated temperatures, often results in problems which include microbial spoilage and development of an imbalance flavor profile; i.e., one not representative of the variety of cheese in question.
Enzyme addition is one route that has been used to accelerate ripening because many cheese varieties in the past have been matured by the action of enzymes associated with milk microflora. However, a problem with enzyme additions is that soluble enzymes, such as lipases and proteases, added to milk before renneting are evenly distributed in both curds and whey. Because curds constitute only a small fraction of the milk volume, the majority of the added enzyme is lost to the much greater volume of whey produced during the cheese making process. Not only is there an uneconomical loss of enzyme, but the resulting whey may be of questionable quality due to excessive fat/protein breakdown from the excess enzyme which needs to be added to achieve adequate levels of enzyme in the curd.
Enzymes could be added directly to the curd before pressing by addition to the salt added during pressing or by spraying a liquid enzyme preparation onto the curds. However, post-renneting addition does not allow for the uniform incorporation of enzyme throughout the curd particles. Furthermore, these methods of distribution are exceedingly difficult to carry out at a factory scale unless special equipment and procedures are employed.
Another method is described in U.S. Pat. No. 4,013,511 Goldstein which discloses use of an immobilized enzyme to make cheese. The immobilization is done by way of an insoluble absorptive resin which is bound to a protease. The resin contributes substantial size to the enzyme (particle is described in the size range of 60-160 microns). Insolubility is achieved and taught in the art by selecting a carrier such as an immobilization agent which is already insoluble for binding to the enzyme. A particular problem with the immobilization agent/enzyme complex in use in food products such as cheese is the difficulty in adding materials that are not approved regulatorily for use in food. Another problem with this method is that the particle size is extremely large and may affect the texture of the curd and resulting cheese.